Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1400782 | European Polymer Journal | 2009 | 11 Pages |
The different rheological behaviour of natural rubber (NR) compared to industrial synthetic poly(cis-1,4-isoprene) (SR) has been attributed to the gel phase and long-chain branching. Previous studies on branching in NR were carried out using the fractionation technique by precipitation to obtain narrow molar mass distribution. In this study, chain branching of poly(cis-1,4-isoprene) in NR was characterised by size-exclusion chromatography coupled with an online multi-angle light scattering detector (SEC-MALS). The nanoaggregates adsorbed on the column packing interfered with branching characterisation for short and medium chains (Mw < 1000 kg/mol). Using a master curve of linear standard poly(cis-1,4-isoprenes), SEC-MALS revealed no or very little branching in the higher chains (1000 < Mw < 10,000 kg/mol) of natural rubber contrary to previous studies. This study showed that the soluble portion of NR samples was composed of almost linear poly(cis-1,4-isoprene) and nanoaggregates with rather compact structures.
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